Ceramic laminated device, communication equipment and method of manufacturing ceramic laminated device

ABSTRACT

In recent years, ceramic laminated devices are becoming a focus of great attention as considerable contribution to the miniaturization of high frequency wireless equipment such as a cellular phone, but it is difficult for the conventional ceramic laminated device to secure reliability while maintaining favorable high frequency characteristics. The present invention provides a ceramic laminated device including a reinforcement electrode, which is formed inside a laminated body in which a plurality of ceramic layers, a plurality of inner electrodes and inter-layer via holes are stacked, not electrically connected with inner electrodes nor inter-layer via holes but mechanically connected with the ceramic layers.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a ceramic laminated device usedfor high frequency wireless equipment such as cellular phone,communication equipment, and method of manufacturing the ceramiclaminated device.

[0003] 2. Related Art of the Invention

[0004] In recent years, ceramic laminated devices are becoming a focusof great attention as considerable contribution to the miniaturizationof high frequency wireless equipment such as a cellular phone.

[0005] Here, a configuration of a conventional ceramic laminated deviceused for high frequency wireless equipment (e.g., Japanese PatentLaid-Open No. 10-303068) will be explained with reference to FIG. 13.

[0006] By the way, the entire disclosure of Japanese Patent Laid-OpenNo. 10-303068 is incorporated herein by reference in its entirety.

[0007]FIG. 13 is a schematic perspective view of a conventional ceramiclaminated device.

[0008] The conventional ceramic laminated device has a structure withceramic layers 61 and electrode patterns 62 alternately stacked.

[0009] The electrode patterns 62 built in a laminated body 63 constitutea high frequency circuit and are mutually electrically connected bymeans of inter-layer via holes 64.

[0010] Furthermore, shield electrodes 65 a and 65 b are formed on thetop and bottom surfaces of the laminated body 63 to keep it shieldedfrom the outside.

[0011] Furthermore, end electrodes 66 a and 66 b which are electricallyconnected with the shield electrodes 65 a and 65b to form groundingterminals, and terminal electrodes 67 a and 67 b which form input/outputterminals for inputting/outputting electric signals to/from the outsideare formed on the right and left end faces of the laminated body 63.

[0012] The conventional ceramic laminated device in the above-describedconfiguration is mounted on a printed circuit board by soldering agrounding electrode (not shown) to the end electrodes 66 a and 66 b andsoldering a high frequency signal electrode (not shown) drawn on theprinted circuit board to the terminal electrodes 67 a and 67 b.

[0013] However, such a configuration of the conventional ceramiclaminated device generally has small folding resistance of lowtemperature sintered ceramic used as the ceramic layer 61. This reducesthe strength of bonding by sintering between the ceramic layer 61, endelectrodes 66 a and 66 b and terminal electrodes 67 a and 67 b.

[0014] As a result, when a reliability test (especially, drop test) isconducted after the mounting on the printed circuit board, (1) thelaminated body 63 may be peeled off the printed circuit board or (2)cracks may occur near joints between the printed circuit board, endelectrodes 66 a and 66 b and terminal electrodes 67 a and 67 b.

[0015] Furthermore, for the conventional ceramic laminated device, whena semiconductor element (semiconductor bare chip) SAW filter, discretecomponent, etc. are soldered to the shield electrode 65 b which isformed on the laminated body 63, solder joints may be weakened.

[0016] Thus, for the conventional ceramic laminated device, it isdifficult to secure reliability while maintaining favorable highfrequency characteristics.

SUMMARY OF THE INVENTION

[0017] The present invention has been implemented in view of theabove-described conventional problems and it is an object of the presentinvention to provide a ceramic laminated device, communication equipmentand method of manufacturing the ceramic laminated device capable ofsecuring reliability while maintaining favorable high frequencycharacteristics.

[0018] The 1^(st) aspect of the present invention is a ceramic laminateddevice comprising an inner part formed inside a laminated body in whicha plurality of ceramic layers (see FIG. 1) and a plurality of electrodelayers are stacked,

[0019] wherein said inner part is not electrically connected with saidelectrode layers but mechanically connected with said ceramic layer.

[0020] The 2^(nd) aspect of the present invention is the ceramiclaminated device according to the 1^(st) aspect, wherein said inner partis a single or a plurality of plane type inner parts providedsubstantially in parallel to said ceramic layer.

[0021] The 3^(rd) aspect of the present invention is the ceramiclaminated device according to the 2^(nd) aspect, further comprisingshield electrodes formed on the upside and/or underside of saidlaminated body,

[0022] wherein said plane type inner part has the same shape as that ofsaid shield electrodes.

[0023] The 4^(th) aspect of the present invention is the ceramiclaminated device according to the 2^(nd) aspect, further comprisingshield electrodes formed on the upside and/or underside of saidlaminated body,

[0024] wherein said plane type inner parts have a shape different fromthat of said shield electrodes.

[0025] The 5^(th) aspect of the present invention is the ceramiclaminated device according to the 1^(st) aspect, further comprisingshield electrodes formed on the upside and/or underside of saidlaminated body

[0026] wherein said inner part is a single or a plurality of solid innerparts provided substantially perpendicular to said ceramic layers on theplane on the side of at least said shield electrodes of said ceramiclayers to which said shield electrodes are pasted.

[0027] The 6^(th) aspect of the present invention is the ceramiclaminated device according to the 2^(nd) aspect, further comprisingshield electrodes formed on the upside and/or underside of saidlaminated body,

[0028] wherein said inner parts are (i) said plane type inner parts, and(ii) a single or a plurality of solid inner parts provided substantiallyperpendicular to said ceramic layers in said ceramic layers between saidshield electrodes and said plane type inner parts.

[0029] The 7^(th) aspect of the present invention is the ceramiclaminated device according to the 6^(th) aspect,

[0030] wherein a plurality of said plane type inner parts are provided,

[0031] at least some of said solid inner parts are provided in saidceramic layer between said plane type inner parts.

[0032] The 8^(th) aspect of the present invention is the ceramiclaminated device according to any one of the 5^(th) to the 7^(th)aspects, wherein said solid inner part is a via hole filled with aconductive paste or dielectric paste.

[0033] The 9^(th) aspect of the present invention is a ceramic laminateddevice comprising:

[0034] side electrodes formed on a side of a laminated body in which aplurality of ceramic layers and a plurality of electrode layers arestacked; and

[0035] an inner part, which is formed inside said laminated body, notelectrically connected with said electrode layers but mechanicallyconnected with said side electrodes.

[0036] The 10^(th) aspect of the present invention is the ceramiclaminated device according to the 9^(th) aspect,

[0037] wherein said side electrodes are terminal electrodes formed onend faces of said laminated body for. inputting/outputting electricsignals to/from the outside, and

[0038] said inner part is a plane type inner part mechanically connectedwith a whole or part of said terminal electrodes and providedsubstantially in parallel to said ceramic layer.

[0039] The 11^(th) aspect of the present invention is the ceramiclaminated device according to the 9^(th) aspect, further comprising anupside shield electrode formed on the upside of said laminated body, andan underside shield electrode formed on the underside of said laminatedbody,

[0040] wherein said side electrodes are end electrodes formed on endfaces of said laminated body for electrically connecting said upsideshield electrode and said underside shield electrode, and

[0041] said inner part is a plane type inner part mechanically connectedwith a whole or part of said end electrodes and provided substantiallyin parallel to said ceramic layer.

[0042] The 12^(th) aspect of the present invention is the ceramiclaminated device according to the 1^(st) or the 9^(th) aspect,

[0043] wherein a semiconductor element and/or SAW filter are mounted onthe upside of said laminated body.

[0044] The 13^(th) aspect of the present invention is the ceramiclaminated device according to the 1 ^(st) or the 9^(th) aspect, whereinsaid laminated body incorporates a filter.

[0045] The 14^(th) aspect of the present invention is the ceramiclaminated device according to the 13^(th) aspect,

[0046] wherein said filter has the function as a duplexer having atransmission filter function to transmit signals and a reception filterfunction to receive signals.

[0047] The 15^(th) aspect of the present invention is communicationequipment comprising:

[0048] communication circuits that carries out a communication usingtransmission and/or reception of signals; and

[0049] the ceramic laminated device according to the 1^(st) or the9^(th) aspect that carries out filtering during said communication.

[0050] The 16^(th) aspect of the present invention is a method ofmanufacturing the ceramic laminated device according to the 1^(st)aspect, comprising an inner part forming step of forming said inner partinside said laminated body in such a way that said inner part is notelectrically connected with said electrode layer but mechanicallyconnected with said ceramic layer.

[0051] The 17^(th) aspect of the present invention is a method ofmanufacturing the ceramic laminated device according to the 9^(th)aspect, comprising an inner part forming step of forming said inner partinside said laminated body in such a way that said inner part is notelectrically connected with said electrode layers but mechanicallyconnected with said side electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0052]FIG. 1 is a schematic perspective view of a ceramic laminateddevice according to Embodiment 1 of the present invention;

[0053]FIG. 2 is an exploded perspective view of a ceramic laminateddevice according to Embodiment 2 of the present invention;

[0054]FIG. 3 is an exploded perspective view of a ceramic laminateddevice according to Embodiment 3 of the present invention;

[0055]FIG. 4 is a sectional view of the ceramic laminated deviceaccording to the embodiment of the present invention;

[0056]FIG. 5 is a sectional view of the ceramic laminated deviceaccording to the embodiment of the present invention;

[0057]FIG. 6 is a schematic perspective view of a ceramic laminateddevice according to Embodiment 4 of the present invention;

[0058]FIG. 7 is a sectional view of the ceramic laminated deviceaccording to the embodiment of the present invention;

[0059]FIG. 8 is a sectional view of a ceramic laminated device accordingto Embodiment 5 of the present invention;

[0060]FIG. 9 is a sectional view of a ceramic laminated device accordingto Embodiment 6 of the present invention;

[0061]FIG. 10 is an exploded perspective view of a ceramic laminateddevice according to Embodiment 7 of the present invention;

[0062]FIG. 11 is a perspective view of a ceramic laminated deviceaccording to Embodiment 8 of the present invention;

[0063]FIG. 12 is a block diagram of a W-CDMA cellular phone according toEmbodiment 9 of the present invention; and

[0064]FIG. 13 is a schematic perspective view of a conventional ceramiclaminated device.

DESIGNATION OF REFERENCE NUMERALS

[0065]1 Laminated body

[0066]2 Inner electrode

[0067]3 Inter-layer via hole

[0068]4 Ceramic layer

[0069]5 a, 5 b Shield electrode

[0070]6 a, 6 b End electrodes

[0071]7 a, 7 b Terminal electrode

[0072]8 Via hole

[0073]11 Laminated body

[0074]12 Inner electrode

[0075]13 Inter-layer via hole

[0076]14 a to 14 g Ceramic layer

[0077]15 a, 15 b Shield electrode

[0078]16 First via hole

[0079]17 First via connection electrode

[0080]18 Second via hole

[0081]19 Second via connection electrode

[0082]21 Laminated body

[0083]22 Ceramic layer

[0084]23 Third via hole

[0085]24 Shield electrode

[0086]25 Third via connection electrode

[0087]31 Ceramic layer

[0088]32 Electrode pattern

[0089]33 Inter-layer via hole

[0090]34 a, 34 b Shield electrode

[0091]35 a to 35 d End electrode

[0092]36 a, 36 b End electrode

[0093]37 a, 37 b Terminal electrode

[0094]38 First inner electrode

[0095]39 Second inner electrode

[0096]41 Laminated body

[0097]42 Semiconductor element

[0098]43 SAW filter

[0099]44 PIN diode

[0100]45 Chip capacitor

[0101]46 Chip resistor

[0102]51 Baseband section

[0103]52 Transmission circuit section

[0104]53 Reception circuit section

[0105]54 Antenna

[0106]55 Duplexer

[0107]61 Ceramic layer

[0108]62 Electrode pattern

[0109]63 Laminated body

[0110]64 Inter-layer via hole

[0111]65 a, 65 b Shield electrode

[0112]66 a, 66 b End electrode

[0113]67 a, 67 b Terminal electrode

PREFERRED EMBODIMENTS OF THE INVENTION

[0114] With reference to the attached drawings, embodiments of thepresent invention will be explained below.

[0115] (Embodiment 1)

[0116] With reference to FIG. 1, the configuration and operation of aceramic laminated device according to this embodiment will be explained.

[0117] By the way, while explaining the configuration and operation ofthe ceramic laminated device of this embodiment, an embodiment of amethod of manufacturing the ceramic laminated device of the presentinvention will also be explained (the same will apply to otherembodiments).

[0118]FIG. 1 is a schematic perspective view of the ceramic laminateddevice according to Embodiment 1 of the present invention.

[0119] The ceramic laminated device of this embodiment has a laminatedbody 1.

[0120] Inner electrodes 2 constituting a high frequency circuit arebuilt in the laminated body 1.

[0121] The inner electrodes 2 are mutually electrically connected bymeans of a plurality of inter-layer via holes 3.

[0122] Each layer electrode pattern formed inside the laminated body 1is formed by means of screen printing, for example, using a conductivepaste predominantly composed of silver or copper.

[0123] The plurality of inter-layer via holes 3 are formed by fillingholes penetrating a ceramic layer 4, which constitutes the laminatedbody 1, with a conductive paste predominantly composed of silver orcopper and sintering them.

[0124] Shield electrodes 5 a and 5 b are formed on the top and bottomsurfaces of the laminated body 1 to keep it shielded from the outside.

[0125] End electrodes 6 a and 6 b which are electrically connected withthe shield electrodes 5 a and 5 b to form grounding terminals andterminal electrodes 7 a and 7 b which form input/output terminals forinputting/outputting electric signals to/from the outside are formed onthe right and left end faces of the laminated body 1.

[0126] A feature of the ceramic laminated device of this embodiment isseen near the bottom of the laminated body 1 of the ceramic layer 4.

[0127] More specifically, a reinforcement electrode 40 for reinforcingthe contact with the layer right above is placed on the top surface ofthe bottom layer of the laminated body 1 of the ceramic layer 4.

[0128] In this way, it is possible to improve the bonding strength ofthe ceramic layer 4 constituting the laminated body 1, and it was provedthrough a reliability test including a drop test that the configurationaccording to this embodiment had excellent stress resistance andreliability.

[0129] (I) By the way, examples of a dielectric material used for theceramic layer include a low relative dielectric constant ceramicmaterial such as Al-Mg-Si-Gd-O base (relative dielectric constant=7.5),high relative dielectric constant ceramic material such as Bi-Ca-Nb-Obase (relative dielectric constant=58) or glass ceramics. However, whileany ceramic material that meets the required electrical characteristicscan be used, it is preferable to use a ceramic material with largefolding resistance wherever possible.

[0130] (II) Furthermore, it is also possible to use ceramic materialswith different dielectric constants for the respective ceramic layers.However, when ceramic materials with different dielectric constants areused, warpageis likely to occur due to a difference in thermal expansioncoefficient during sintering. For this reason, it is preferable thatceramic materials be placed symmetrically with respect to the laminationdirection (e.g., in the order of material A, material B, material C,material B, and material A).

[0131] By the way, the ceramic layer 4 corresponds to the ceramic layerof the present invention, the means including the inner electrodes 2 andinter-layer via holes 3 corresponds to the electrode layer of thepresent invention, the laminated body 1 corresponds to the laminatedbody of the present invention and the reinforcement electrode 40corresponds to the plane type inner part of the present invention.

[0132] (Embodiment 2)

[0133] With reference to FIG. 2, the configuration and operation of aceramic laminated device according to this embodiment will be explained.

[0134]FIG. 2 is an exploded perspective view of the ceramic laminateddevice according to Embodiment 2 of the present invention.

[0135] The ceramic laminated device of this embodiment has a laminatedbody with electrode patterns 32 formed on the surface of 6 ceramiclayers 31.

[0136] The electrode patterns 32 are electrically connected by means ofinter-layer via holes 33.

[0137] Shield electrodes 34 a and 34 b are formed on the top and bottomsurfaces of the laminated body to keep it shielded from the outside.

[0138] End electrodes 35 a to 35 d and 36 a and 36 b which are connectedwith the shield electrodes 34 a and 34 b to form grounding terminals andterminal electrodes 37 a and 37 b which form input/output terminals forinputting/outputting electric signals to/from the outside are formed onthe right and left end faces of the laminated body.

[0139] A feature of the ceramic laminated device of this embodiment isseen near the bottom of the laminated body of the ceramic layers 31.

[0140] More specifically, a reinforcement electrode 40 a for reinforcingthe contact with the layer right above is placed on the top surface ofthe bottom layer of the laminated body 1 of the ceramic layers 31. Thereinforcement electrode 40 a has the same shape as that of the shieldelectrodes 34 a and 34 b.

[0141] In this way, it is possible to improve the bonding strength ofthe ceramic layers 31 constituting the laminated body, and it was provedthrough a reliability test including a drop test that the configurationaccording to this embodiment had excellent stress resistance andreliability.

[0142] (I) By the way, in addition to this, similar effects can also beobtained with respect to the number of electrodes, shape and thickness.

[0143] By the way, the ceramic layers 31 correspond to the ceramiclayers of the present invention, the means including the electrodepatterns 32 and inter-layer via holes 33 corresponds to the electrodelayer of the present invention, the shield electrodes 34 a and 34 bcorrespond to the shield electrodes of the present invention and thereinforcement electrode 40 a corresponds to the plane type inner part ofthe present invention.

[0144] (Embodiment 3)

[0145] With reference to FIG. 3, the configuration and operation of aceramic laminated device according to this embodiment will be explained.

[0146]FIG. 3 is an exploded perspective view of the ceramic laminateddevice according to Embodiment 3 of the present invention.

[0147] A feature of a ceramic laminated device of this embodiment isseen near the bottom of the laminated body of the ceramic layers 31 (therest of the configuration is the same as that of the ceramic laminateddevice of aforementioned Embodiment 2, and therefore detailedexplanations thereof will be omitted).

[0148] More specifically, reinforcement electrodes 40 b and 40 c forreinforcing the contact with the layer right above are placed on the topsurface of the bottom layer of the laminated body of the ceramic layers31. The reinforcement electrodes 40 b and 40 c have a different shapefrom that of the shield electrodes 34 a and 34 b.

[0149] In this way, it is possible to improve the bonding strength ofthe ceramic layers 31 constituting the laminated body, and it was provedthrough a reliability test including a drop test that the configurationaccording to this embodiment had excellent stress resistance andreliability.

[0150] (I) By the way, in aforementioned Embodiments 1 to 3, the numberof ceramic layers on which the reinforcement electrode is placed is one,but the number is not limited to one, and there may be two or more suchceramic layers (see FIG. 4 and 5).

[0151] However, increasing the number of ceramic layers where such areinforcement electrode is placed has a tendency to shorten anelectrical distance between upper and lower shield electrodes.

[0152] For example, in FIG. 4, since reinforcement electrodes 40 d and40 e are placed, the electrical distance between the shield electrodes34 a and 34 b becomes distance X. Furthermore, in FIG. 5, sincereinforcement electrodes 40 f and 40 g are placed, the electricaldistance between shield electrodes 34 a and 34 b becomes distance Y.

[0153] For this reason, when there are too many ceramic layers wherereinforcement electrodes are placed, the characteristic of the highfrequency circuit formed inside the laminated body may deteriorate.Therefore, there are preferably not too many ceramic layers where thereinforcement electrodes are placed.

[0154] However, as in the case of aforementioned Embodiment 3, when thereinforcement electrodes have a shape different from that of the shieldelectrodes, providing a gap in the center of the reinforcement electrode(that is, a place where no electrode printing is performed) will preventthe electrical distance between the upper and lower shield electrodesfrom shortening.

[0155] Of course, as in the case of aforementioned Embodiment 2, whenthe reinforcement electrodes have the same shape as that of the shieldelectrodes, there is an advantage that the manufacturing process issimpler.

[0156] (II) Furthermore, when the reinforcement electrodes are arrangedsymmetrically with respect to the lamination direction, warpage isunlikely to occur due to a difference in thermal expansion coefficientduring sintering, and therefore preferable effects can be expected (seeFIG. 5).

[0157] By the way, the ceramic layers 31 correspond to the ceramiclayers of the present invention, the means including the electrodepatterns 32 and inter-layer via holes 33 corresponds to the electrodelayer of the present invention, the shield electrodes 34 a and 34 bcorrespond to the shield electrodes of the present invention and thereinforcement electrodes 40 b and 40 c correspond to the plane typeinner parts of the present invention.

[0158] (Embodiment 4)

[0159] With reference to FIG. 6, the configuration and operation of aceramic laminated device of this embodiment will be explained.

[0160]FIG. 6 is a schematic perspective view of the ceramic laminateddevice according to Embodiment 4 of the present invention.

[0161] A feature of the ceramic laminated device of this embodiment isseen near a shield electrode 5 a formed below a laminated body 1 (therest of the configuration is the same as the configuration of theceramic laminated device of Embodiment 1, and therefore detailedexplanations thereof will be omitted).

[0162] More specifically, in the layer at the bottom of the laminatedbody 1 of ceramic layer 4 are placed a plurality of via holes 8 whoseone end is mechanically connected with the shield electrode 5 a formedon the underside of the laminated body 1 and whose other end iselectrically open.

[0163] The via holes 8 are formed by filling holes penetrating theceramic layer 4, which constitutes the laminated body 1, with aconductive paste (or dielectric paste) and sintering them. The via holes8 are via holes intended to secure the contact between the ceramic layer4 and the shield electrode 5 a.

[0164] In this way, it is possible to improve the bonding strength ofthe ceramic layer 4 constituting the laminated body 1 and theshieldelectrode5 a, and it was proved through a reliability testincluding a drop test that the configuration according to thisembodiment had excellent stress resistance and reliability.

[0165] More specifically, in such a reliability test, there was neitherpeeling from the printed circuit board, cracks in the end electrodes 6 aand 6 b and terminal electrodes 7 a and 7 b, nor cracks in the laminatedbody 1.

[0166] The laminated body 1 actually built as a prototype of thisembodiment has dimensions of breadth 8.5 mm×depth 4.5 mm×height 2.0 mm.

[0167] Then, in the shield electrode 5 a, which is the underside of thelaminated body 1, 15 via holes 8 of 140 μm in length whose one end isconnected to the shield electrode 5 a and whose other end is open areplaced virtually equidistantly.

[0168] Five laminated bodies 1 of this embodiment and five conventionallaminated bodies were each soldered equidistantly to a printed circuitboard.

[0169] Then, when a drop test was conducted, most of the conventionallaminated bodies had defects like laminated body peeling from theprinted circuit board or having cracks, whereas none of the fivelaminated bodies 1 of this embodiment had such defects.

[0170] Therefore, it was observed that reliability improved drasticallyand sufficient effects were obtained.

[0171] By the way, the ceramic layer 4 corresponds to the ceramic layerof the present invention, the means including the inner electrodes 2 andinter-layer via holes 3 corresponds to the electrode layer of thepresent invention, the laminated body 1 corresponds to the laminatedbody of the present invention, the shield electrodes 5 a and 5 bcorrespond to the shield electrodes of the present invention, the viaholes 8 correspond to the via holes provided in the ceramic layer towhich the shield electrodes of the present invention are pasted.

[0172] (Embodiment 5)

[0173] With reference to FIG. 8, the configuration and operation of aceramic laminated device according to this embodiment will be explained.

[0174]FIG. 8 is a sectional view of the ceramic laminated deviceaccording to Embodiment 5 of the present invention.

[0175] The ceramic laminated device of this embodiment has a laminatedbody 11.

[0176] Inner electrodes 12 constituting a high frequency circuit arebuilt in the laminated body 11.

[0177] The inner electrodes 12 are mutually electrically connectedthrough inter-layer via holes 13.

[0178] The inter-layer via holes 13 are formed by filling holespenetrating the ceramic layers 14 a to 14 g constituting the laminatedbody 11 with a conductive paste predominantly composed of silver orcopper and sintering them.

[0179] Shield electrodes 15 a and 15 b are formed on the top and bottomsurfaces of the laminated body 11 to keep it shielded from the outside.

[0180] As in the case of aforementioned Embodiment 1, terminalelectrodes (not shown) and end electrodes (not shown) are formed on theend faces of the laminated body 11.

[0181] On the upside of the first ceramic layer 14 a at the bottom isplaced a plane type first via connection electrode 17, which does notfunction as a circuit element.

[0182] On the upside of the second ceramic layer 14 b is placed a planetype second via connection electrode, 19 which does not function as acircuit element.

[0183] The first ceramic layer 14 a at the bottom of the laminated body11 is provided with a plurality of first via holes 16 to mechanicallyconnect a shield electrode 15 a formed on the underside of the laminatedbody 11 and a first via connection electrode 17.

[0184] The second ceramic layer 14 b on top of the first via connectionelectrode is provided with a plurality of second via holes 18 tomechanically connect the first via connection electrode 17 and thesecond via connection electrode 19.

[0185] The first via holes 16 are formed by filling holes penetratingthe ceramic layers constituting the laminated body 11 with a conductivepaste (or dielectric paste) and sintering them. The first via holes 16are via holes intended to secure the contact between the first viaconnection electrode 17 and the shield electrode 15 a.

[0186] The second via holes 18 are formed by filling holes penetratingthe ceramic layers constituting the laminated body 11 with a conductivepaste (or dielectric paste) and sintering them. The second via holes 18are via holes intended to secure the contact between the second viaconnection electrode 19 and the first via connection electrode 17.

[0187] In this way, it is possible to improve the bonding strength ofthe ceramic layers 14 a and 14 b and the shield electrode 15 a, and itwas proved through a reliability test including a drop test that theconfiguration according to this embodiment had excellent stressresistance and reliability.

[0188] (I) By the way, the number of via connection electrodes toimprove the bonding strength in this embodiment is 2, but the number isnot limited to this, and the number of the via connection electrode canalso be 1 (see FIG. 7) or 3 or more.

[0189] However, increasing the number of via connection electrodes has atendency to shorten an electrical distance between upper and lowershield electrodes.

[0190] For example, in FIG. 7, since the via connection electrode 17 ais placed, the electrical distance between the shield electrodes 15 aand 15 b becomes distance Z.

[0191] For this reason, when there are too many via connectionelectrodes the characteristic of the high frequency circuit formedinside the laminated body may deteriorate. Therefore, there arepreferably not too many via connection electrodes.

[0192] (II) Furthermore, when the via connection electrodes are arrangedsymmetrically with respect to the lamination direction, warpage isunlikely to occur due to a difference in thermal expansion coefficientduring sintering, and therefore preferable effects can be expected.

[0193] By the way, the ceramic layers 14 a to 14 g correspond to theceramic layers of the present invention, the means including the innerelectrodes 12 and inter-layer via holes 13 corresponds to the electrodelayers of the present invention, the laminated body 11 corresponds tothe laminated body of the present invention, the shield electrodes 15 aand 15 b correspond to the shield electrodes of the present invention,the first via connection electrode 17 and second via connectionelectrode 19 correspond to the plane type inner parts of the presentinvention, the first via holes 16 correspond to the via holes providedin the ceramic layer between the shield electrode and plane type innerpart of the present invention, the second via holes 18 correspond to thevia holes provided in the ceramic layer between a plurality of planetype inner parts of the present invention (at least some of the viaholes are provided in the ceramic layer 14 b between the first viaconnection electrode 17 and the second via connection electrode 19 inthe ceramic layers 14 a to 14 g).

[0194] (Embodiment 6)

[0195] With reference to FIG. 9, the configuration and operation of aceramic laminated device of this embodiment will be explained.

[0196]FIG. 9 is a sectional view of the ceramic laminated deviceaccording to Embodiment 6 of the present invention.

[0197] A feature of the ceramic laminated device of this embodiment isseen near the upper part of a laminated body 21 (the rest of theconfiguration is similar to the configuration of the ceramic laminateddevice according to Embodiment 5, and therefore detailed explanationsthereof will be omitted).

[0198] More specifically, on the underside of the ceramic layer 22located at the top is further placed a plane type third via connectionelectrode 25, which does not function as a circuit element.

[0199] In the ceramic layer 22 located at the top of the laminated body21 are placed a plurality of third via holes 23 to mechanically connecta shield electrode 24 formed on the upside of the laminated body 21 andthe third via connection electrode 25.

[0200] The third via holes 23 are formed by filling holes penetratingthe ceramic layers constituting the laminated body 21 with a conductivepaste (or dielectric paste) and sintering them. The third via holes 23are via holes intended to secure the contact between the third viaconnection electrode 25 and shield electrode 24.

[0201] In this way, it is possible to provide a ceramic laminated devicewith excellent reliability.

[0202] More specifically, when a semiconductor element, semiconductorpackage, SAW filter and discrete component are mounted on the laminatedbody 21, it is possible to reinforce bonding strength between theceramic layer 22 and the shield electrode 24 thereupon. Here, in thecase of a semiconductor element, a stack bump bonding (SBB) method, etc.may be used as the mounting method.

[0203] By the way, the ceramic layer 22 corresponds to the ceramic layerof the present invention, the laminated body 21 corresponds to thelaminated body of the present invention, the shield electrode 24corresponds to the shield electrode of the present invention, the thirdvia connection electrode 25 corresponds to the plane type inner part ofthe present invention and the third via holes 23 correspond to the viaholes provided in the ceramic layer between the shield electrode andplane type inner part of the present invention.

[0204] (Embodiment 7)

[0205] With reference to FIG. 10, the configuration and operation of aceramic laminated device according to this embodiment will be explained.

[0206]FIG. 10 is an exploded perspective view of the ceramic laminateddevice according to Embodiment 7 of the present invention.

[0207] A feature of the ceramic laminated device of this embodiment isseen near the surface of a plurality of ceramic layers 31 (the rest ofthe configuration is the same as the configuration of the ceramiclaminated device of Embodiment 2, and therefore detailed explanationsthereof will be omitted).

[0208] More specifically, on the surface of a plurality of ceramiclayers 31 are placed first inner electrodes 38 that do not function as acircuit element (enclosed by a rectangle with round corners for ease ofunderstanding). The first inner electrodes 38 are provided substantiallyperpendicular to the terminal electrodes 37 a and 37 b that forminput/output terminals to input/output electric signals to/from theoutside and mechanically connected with the terminal electrodes 37 a and37 b.

[0209] On the surface of the plurality of ceramic layers 31 are placedsecond inner electrodes 39 that do not function as a circuit element(enclosed by a rectangle with round corners for ease of understanding).The second inner electrode 39 is provided substantially perpendicular tothe end electrode 36 b that connects the shield electrodes 34 a and 34 band mechanically connected with the end electrode 36 b.

[0210] Thus, there is a drastic increase in the number of connectionsbetween the first inner electrodes 38 and terminal electrodes 37 a and37 b and connections between the second inner electrode 39 and endelectrode 36 b. This drastically increases the bonding strength betweenthe laminated body and external electrodes consisting of the terminalelectrodes 37 a and 37 b and end electrode 36 b, etc.

[0211] In this way, it is possible to prove through a reliability testincluding a drop test that the configuration according to thisembodiment has excellent reliability and provide a ceramic laminateddevice with high stress resistance.

[0212] The laminated body actually built as a prototype of thisembodiment has dimensions of breadth 8.5 mm×depth 4.5 mm ×height 2.0 mm.

[0213] 8 first inner electrodes 38 are connected with the terminalelectrodes 37 a and 37 b formed on the surface of the laminated body.

[0214] When the terminal electrodes 37 a and 37 b had a width of 1.0 mmand the first inner electrode 38 having a depth of 0.5 mm was connectedthereto, there were no longer defects such as peeling from the printedcircuit board or cracks during a drop test.

[0215] Therefore, it was confirmed that reliability was improveddrastically and sufficient effects were obtained.

[0216] By the way, the ceramic layers 31 correspond to the ceramiclayers of the present invention, the means including the electrodepatterns 32 and inter-layer via holes 33 corresponds to the electrodelayers of the present invention, the terminal electrodes 37 a and 37 bcorrespond to the terminal electrodes of the present invention, thefirst inner electrodes 38 correspond to the plane type inner partsconnected to the terminal electrodes of the present invention, theshield electrode 34 b corresponds to the upside shield electrode of thepresent invention, the shield electrode 34 a corresponds to theunderside shield electrode of the present invention, the end electrodes35 a to 35 d and 36 a and 36 b correspond to the end electrodes of thepresent invention and the second inner electrode 39 corresponds to theplane type inner part connected to end electrodes of the presentinvention.

[0217] (Embodiment 8)

[0218] With reference to FIG. 11, the configuration and operation of aceramic laminated device according to this embodiment will be explained.

[0219]FIG. 11 is a perspective view of the ceramic laminated deviceaccording to Embodiment 8 of the present invention.

[0220] On the upside of a laminated body 41 of the ceramic laminateddevice of this embodiment, a semiconductor element 42, a SAW filter 43,a PIN diode 44, a chip capacitor 45 and a chip resistor 46 are mounted.

[0221] More specifically, for example, the semiconductor element 42 is atransistor such as a low noise amplification circuit mounted on thesurface of the laminated body 41 and electrically connected with a highfrequency circuit formed inside the laminated body 41 through aconnection electrode formed on the surface of the laminated body 41.Here, the high frequency circuit is a laminated filter, etc.

[0222] A circuit element such as the semiconductor element 42 can beunited with the circuit elements such as a capacitor and inductor formedinside and on the surface of the laminated body 41. Thus, the presentinvention is expected to contribute to the miniaturization of a cellularphone with more sophisticated functions.

[0223] Using the aforementioned ceramic laminated device according toEmbodiments 1 to 7 as the laminated body 41 can provide a highreliability ceramic laminated device. Furthermore, it can also improveyield in the manufacturing stage.

[0224] By the way, the laminated body 41 corresponds to the laminatedbody of the present invention, the circuit including the semiconductorelement 42 corresponds to the semiconductor element of the presentinvention, and the SAW filter 43 corresponds to the SAW filter of thepresent invention.

[0225] (Embodiment 9)

[0226] With reference to FIG. 12, the configuration and operation of aW-CDMA (Wideband-Code Division Multiplex Access) cellular phoneaccording to this embodiment will be explained.

[0227]FIG. 12 is a block diagram of the W-CDMA cellular phone accordingto Embodiment 9 of the present invention.

[0228] For the W-CDMA cellular phone of this embodiment, the ceramiclaminated device of the aforementioned embodiment is used.

[0229] A signal output from the baseband section 51 is input to thetransmission circuit section 52 and output as a signal with atransmission frequency.

[0230] On the other hand, a signal with a reception frequency led froman antenna 54 is input to the reception circuit section 53, converted inthe reception circuit section 53 from a signal with a receptionfrequency to a signal with a frequency of the baseband section 51 andoutput to the baseband section 51.

[0231] A duplexer 55 has the function of separating a transmissionsignal and reception signal.

[0232] Using the ceramic laminated device of the aforementionedembodiment can realize a high reliability cellular phone.

[0233] (I) By the way, this embodiment uses a duplexer used for a W-CDMAcellular phone, but it is also possible to use a duplexer used in othercellular phone systems such as GSM (Global System for MobileCommunication) system and PDC (Personal Digital Cellular) system.

[0234] (II) Furthermore, the ceramic laminated device can also havefunctions other than that of the duplexer.

[0235] By the way, the duplexer 55 corresponds to the duplexer of thepresent invention and the means including the baseband section 51,transmission circuit section 52 and reception circuit section 53corresponds to the communication circuit of the present invention.

[0236] Embodiments 1 to 9 have been explained in detail so far.

[0237] By the way, the ceramic layer provided with the shield electrodesaccording to the present invention, for example, of Embodiment 4 above,is provided with penetrating via holes 8 filled with a conductive paste(or dielectric paste) , but the present invention is not limited to thisand via holes provided at least on the plane of the shield electrode canmake the same effect (such via holes may or may not penetrate theceramic layer) In short, any ceramic layer provided with the shieldelectrode of the present invention is acceptable if it is at leastprovided with a solid inner part substantially perpendicular to theceramic layer on the plane of the shield electrode.

[0238] Furthermore, the ceramic layer provided with the via holes of thepresent invention, for example, of Embodiment 4 above, is the shieldelectrode 5 a formed on the underside of the laminated body, but theceramic layer is not limited to this. In short, any ceramic layer isacceptable if it is at least provided with the shield electrode formedon the upside and/or underside of the laminated body.

[0239] Furthermore, the plane type inner part connected to the terminalelectrodes of the present invention, for example, of Embodiment 7, isthe first inner electrode 38 connected to the terminal electrodes 37 aand 37 b, but the plane type inner part is not limited to this. Inshort, any plane type inner part is acceptable if it is mechanicallyconnected with a whole or part of the terminal electrode.

[0240] Furthermore, the plane type inner part connected to the endelectrodes of the present invention, for example, of Embodiment 7, isthe second inner electrode 39 connected to the end electrode 36 b, butthe plane type inner part is. not limited to this. In short, any planetype inner part is acceptable if it is mechanically connected with awhole or part of the end electrode.

[0241] Thus, by directly connecting (1) electrodes, (2) via holes and(3) shield electrodes, terminal electrodes and end electrodes formedinside the laminated body that constitute the ceramic laminated device,it is possible to improve the bonding strength between the laminatedbody and the external electrodes.

[0242] Then, it is possible to provide a ceramic laminated device withsecured reliability supported by excellent results of variousreliability tests such as drop test, ensuring no peeling from theprinted circuit board nor cracks in the laminated body.

[0243] As is apparent from the explanations above, the present inventionhas the advantage of providing a ceramic laminated device capable ofsecuring reliability while maintaining favorable high frequencycharacteristics.

What is claimed is:
 1. A ceramic laminated device comprising an innerpart formed inside a laminated body in which a plurality of ceramiclayers (see FIG. 1) and a plurality of electrode layers are stacked,wherein said inner part is not electrically connected with saidelectrode layers but mechanically connected with said ceramic layer. 2.The ceramic laminated device according to claim 1, wherein said innerpart is a single or a plurality of plane type inner parts providedsubstantially in parallel to said ceramic layer.
 3. The ceramiclaminated device according to claim 2, further comprising shieldelectrodes formed on the upside and/or underside of said laminated body,wherein said plane type inner part has the same shape as that of saidshield electrodes.
 4. The ceramic laminated device according to claim 2,further comprising shield electrodes formed on the upside and/orunderside of said laminated body, wherein said plane type inner partshave a shape different from that of said shield electrodes.
 5. Theceramic laminated device according to claim 1, further comprising shieldelectrodes formed on the upside and/or underside of said laminated bodywherein said inner part is a single or a plurality of solid inner partsprovided substantially perpendicular to said ceramic layers on the planeon the side of at least said shield electrodes of said ceramic layers towhich said shield electrodes are pasted.
 6. The ceramic laminated deviceaccording to claim2, further comprising shield electrodes formed on theupside and/or underside of said laminated body, wherein said inner partsare (i) said plane type inner parts, and (ii) a single or a plurality ofsolid inner parts provided substantially perpendicular to said ceramiclayers in said ceramic layers between said shield electrodes and saidplane type inner parts.
 7. The ceramic laminated device according toclaim 6, wherein a plurality of said plane type inner parts areprovided, at least some of said solid inner parts are provided in saidceramic layer between said plane type inner parts.
 8. The ceramiclaminated device according to any one of claims 5 to 7, wherein saidsolid inner part is a via hole filled with a conductive paste ordielectric paste.
 9. A ceramic laminated device comprising: sideelectrodes formed on a side of a laminated body in which a plurality ofceramic layers and a plurality of electrode layers are stacked; and aninner part, which is formed inside said laminated body, not electricallyconnected with said electrode layers but mechanically connected withsaid side electrodes.
 10. The ceramic laminated device according toclaim 9, wherein said side electrodes are terminal electrodes formed onend faces of said laminated body for inputting/outputting electricsignals to/from the outside, and said inner part is a plane type innerpart mechanically connected with a whole or part of said terminalelectrodes and provided substantially in parallel to said ceramic layer.11. The ceramic laminated device according to claim 9, furthercomprising an upside shield electrode formed on the upside of saidlaminated body, and an underside shield electrode formed on theunderside of said laminated body, wherein said side electrodes are endelectrodes formed on end faces of said laminated body for electricallyconnecting said upside shield electrode and said underside shieldelectrode, and said inner part is a plane type inner part mechanicallyconnected with a whole or part of said end electrodes and providedsubstantially in parallel to said ceramic layer
 12. The ceramiclaminated device according to claim 1 or 9, wherein a semiconductorelement and/or SAW filter are mounted on the upside of said laminatedbody.
 13. The ceramic laminated device according to claim 1 or 9,wherein said laminated body incorporates a filter.
 14. The ceramiclaminated device according to claim 13, wherein said filter has thefunction as a duplexer having a transmission filter function to transmitsignals and a reception filter function to receive signals. 15.Communication equipment comprising: communication circuits that carriesout a communication using transmission and/or reception of signals; andthe ceramic laminated device according to claim 1 or 9 that carries outfiltering during said communication.
 16. A method of manufacturing theceramic laminated device according to claim 1, comprising an inner partforming step of forming said inner part inside said laminated body insuch a way that said inner part is not electrically connected with saidelectrode layer but mechanically connected with said ceramic layer. 17.A method of manufacturing the ceramic laminated device according toclaim 9, comprising an inner part forming step of forming said innerpart inside said laminated body in such a way that said inner part isnot electrically connected with said electrode layers but mechanicallyconnected with said side electrodes.